Fuel mixing device



Patented Aug. 3, 1954 UNITED STATES ATENT OFFICE 9 Claims.

The present invention relates to fuel mixing devices and is primarily concerned with a new and greatly improved accessory mixing unit for use primarily in internal combustion engines for improving the economy and performance thereof by more completely mixing and vaporizing the stream of fuel and air between the carburetor and the intake port of the engine block. The present application is a continuation-in-part of my earlier application Serial No. 271,664, filed February 15, 1952.

Heretofore a wide variety of devices and arrangements have been proposed to promote more complete vaporization of the fuel and homogenization of the fuel and air mixture in order to increase the efficiency of internal combustion engines. Some of these prior art devices are shown and described in such United States patents as Nos. 1,186,386; 1,580,050; 2,216,846; and 1,298,314, as well as in French Patent No. 604,471 dated January 26, 1926, over which various constructions the present device is a distinct improvement.

Speaking in general terms, there are two major factors which I believe have largely prevented any of these earlier devices from operating satisfactorily, at least from a commercial point of View. Perhaps the more important of these two factors is the failure to appreciate the importance of avoiding the production of internal turbulence in the fuel stream and reducing the centrifuging of the liquid particles against the wall of the conduit. Vaporization of centrifuged particles tends to be inhibited while the existence of such turbulence greatly impairs the volumetric efficiency of the engine, thereby canceling out any gains which might be expected from any improved homogenization.

The second factor which I believe to have been largely overlooked by the prior art workers is the importance of positioning the mixing device at a point in the system to employ engine heat for increasing the temperature of the mixing blades, thereby preheating the fuel mixture and promoting more rapid vaporizaton of the fuel. It will be noted that most of these earlier patents teach the installation of their devices either in the carburetor outlet itself or relatively close thereto and, in most cases, in advance of sharply angled portions of the fuel line where any liquid particles will separate out. I have found that greatly improved results may be obtained by installing the mixing device of the present invention directly at the joint between the fuel conduit from the carburetor and the intake port of the engine block, with portions of the novel vout the creation of unit in direct thermal contact with the metal of the engine block so as effectively to transmit heat to the mixing blades. In straight six automobile engines this usually means the use of three instead of a single unit, since a single intake port in most engines of this type serves a pair of cylinders. Thus, by the novel construction and the special dimensions, shape and adjustment of the blades of my mixing device, as hereinafter more fully described, I avoid the creation of turbulence and reduce the centrifuging effect upon liquid fuel particles; by employing a sheet metal of high thermal conductance and mounting the same in direct thermal contact with the engine block, I am able at the same time to preheat the stream as it passes through the blades improving vaporization of the fuel prior to introduction into the combustion chamber.

With the foregoing in mind, a primary object of my invention, therefore, is the provision of a new, improved and greatly simplified mixing device for installation between the carburetor and air intake port of an internal combustion engine, preferably directly within such port, for improving the vaporization of the fuel and homogenization of the fuel and air mixture withinternal turbulence or centrifuging out liquid particles of fuel, thereby effecting fuel economics while improving the performance of the engine.

A further object of the invention is to provide a fuel mixing device of the type described which will assure almost complete combustion in the combustion chamber, thereby preventing the deposit of carbon with resultant knocking of the engine.

Another object of the invention is the provision of an improved fuel econornizer of the type described which preferably may be formed from two easily stamped out blanks of sheet metal having special interlocking portions for holding them securely together in the desired cylindrical form.

Yet another object of the invention is the provision of a mixing device so mounted and composed of such thermal conductive material as to conduct heat efficiently to the fuel mixture passing therethrough thereby assuring complete vaporization of the fuel prior to introduction into the firing chamber.

In accordance with the invention l form my novel mixing device from one or more sheet metal blanks, suitably stamped from a piece of sheet for maximum convenience and economy, to form a single device, each blank being bent into arouate form and being provided with interlocking portions, preferably comprising fingers and slots at opposite lateral edges, which serve to interlock the two pieces generally in the form of a complete cylinder of the proper diameter to fit within the conduit in Which it is to be mounted. The metallic material composing each blank preferably has characteristics of high thermal conductivity. A beryllium copper alloy, I have found, combines excellent properties of heat and conductivity with strength and oxidation resistance at high temperatures. Each blank likewise has struck from its outer end (i. e., the end which will face the stream of air and fuel) a series of parallel side-by-side blades directed at an angle of from about 30 to 40 to the transverse axis of the flat blank. When the blank is turned into arcuate form, these blades are bent inwardly upon themselves in a generally semicircular recurving manner so that their tips are near to but spaced from the longitudinal axis of the device and are closer to the transverse axis thereof than the semicircular recurving portions of such blades. The planes of the semicircles thus defined are also at an angle of 30 to 40 to the transverse axis and all of which intersect at the center of the device. The blades form a spiral appearing series through which the passing stream of fuel and air must travel, the direction of curvature being such as to impart a whirling motion thereto in one direction only. Each member has struck from the opposite end a series of turbine blades which are bent so as to converge in a conical manner. These blades are rectangular and of a length approximating the diameter of the intake port in which the device is to be mounted. Each of these blades is uniformly twisted from base to tip for a total twist of about 90 all in the same direction so as to impart a whirling motion to the fuel mixture passing therethrough in a direction opposite to that imparted by the other set of blades. Alternating between these long rectangular blades is a series of short projections or ears which are bent radially outwardly 90 to form anchoring lugs Which fit between a mounting fiange on the fuel conduit and an area surrounding the intake `manifold of the engine, but in thermal contact with the metal of the engine block. Each blank is likewise provided with means for interlocking with each other, such means in one form comprising a transverse tongue on one side and a pair of spaced transverse tongues at the other side. Along the transverse center line of each blank and near the pair of outwardly extending tongues, I provide one or more longitudinally extending narrow slots. These tongues and slots are arranged to coact with each other for locking the blanks together to form the cylindrical completed mixing unit.

Still further objects, features and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof taken together with the accompanying drawings in which like numerals refer to like parts in the several views and in which:

Fig. 1 is a longitudinal sectional view through the end portion of the fuel conduit and the fuel intake portion of the engine block to which it is attached, with my novel fuel-saving device installed at the joint;

Fig. 2 is a -plan View on a somewhat reduced scale of one of the sheet metal blanks ofwhich my device is formed;

Fig. 3 is a transverse Sectional view taken on line 3--3of Fig. 1 showing the formed device, but onitting the adjacent engine components; and

Fig. 4 is an end view taken on line --d of Fig. 1.

The numeral it denotes the end of the fuel conduit which runs from the outlet of the carburetor to the intake port it in the engine block IS of an internal combustion engine. The pipe ie is provided with a fiange ill and the portion of the cylinder block 13 surrounding the intake opening IB is drilled and tapped to receive machine screws l8 for joining the pipe ID thereto by means of the flange. The joint is made using a sealing gasket 29. My novel mixing device, indicated generally by the numeral l2, is mounted in a manner hereinafter more fully described, and this joint held securely by tightening the machine screws l8.

The mixing device itself is formed from a pair of sheet metal blanks 213, only one of which is shown in Fig. 2, since they are preferably identical. As seen in Fig. 2, the major or longitudinal axis thereof is indicated by the line ;u -:c and the transverse or minor axis is indicated by the line y-y. The blank has struck from it at each end a series of specially formed and shaped blades. The blades of one of these series are denoted by the numeral 26, each blade being of substantial length, approaching the diameter z-z of the conduit in which the mixing device is to be mounted. Alternating with these elongated rectangular blades is a series of pointed ears 2I8 for a purpose hereinafter indicated. From the other end of the blank 2d (on its major axis) is struck a second series of blades 30, these blades being directed at a predetermined angle to the transverse axis y-y of the blank. This angle will depend somewhat upon the dimensions of the conduit, but I have found that in most cases the angle should be within the limits of approximately 3G to 40 for best results. This angle determines the directions of the planes of the semicircles into Which these blades Will be bent as hereinafter indicated.

From the lower side (relative to minor axis 21-11) of the blank, projects a tongue 32 and from the opposite side projects a corresponding pair of spaced parallel tongues 3d. Near the side of the blank carrying the tongues 34, I provide a series of slots 36 running in a direction parallel with the axis :c-cc and the width of any of which, in a longitudinal direction, is sufiicient to accommodate the tongue 32. The slots are spaced from each other along the axis y--y.

As shown in the drawings, the mixing device is preferably formed by bonding a pair of the flat blanks 2d, as illustrated in Fig. 2, into arouate form so that together they will form substantially a complete cylinder whose external diameter coz-responds with the internal diameter e z of the conduit Hi. By selection of an appropriate slot 36 in which to fit the tongue 32, the diameter of my device may be easily varied within certain limits. A tongue 32 of each blank is bent outwardly and forced through the appropriate slot 36. The opposed tongues 3d are bent backwardly across the shoulders 38 on either side of the base of the tongue 32 to lock the two sections of the device more securely to each other. The tabs 28 are all bent radially outwardly and iit beneath the gasket 2% and against the surface of the block it making good thermal contact therewith. The blades 25 are defiected toward each other and they converge in a conical fashion leaving asmall opening between the tips thereof, as best seen in Fig. 3, and each blade is twisted uniformly from base to tip for a total twist of approximately 90, all of the blades being so twisted in the same direction so as to impart a smooth whirling motion to thev gaseous mixture which passes therethrough. The blades 3d, on the other end, which project more or less diagonally from the blank, are bent into gently recurving semicircular form with the blade tips located in the same transverse plane and leaving a uniform axial opening therebetween corresponding to the opening between the tips of the blades 23. The recurving portions of the blades slightly overlap each other, as best seen in Figs. l and ll, defining uniformly angled curved passageways therebetween. It will be noted that the tips of the blades 39 define a plane a-a which is close to the plane defined by the points of attachment of such blades to the body of the member. Thus the recurving portions of these blades project further upstream into the conduit lil than do the tips or bases of the blades. These recurving blades 30 form a spiral appearance as viewed in Fig. 4 and their arcuate surfaces are uniformly parallel to each other and so directed as to impart a smooth whirling motion to the fuel mixture Which enters from the direction inclicated by the arrow in Fig. 1, the direction of rotation of the mixture being opposite to the motion which is subsequ'ently imparted by the action of the blades 26. The curved blades 3d lie in a series of parallel planes all of which meet upon the axis of the conduit IO and which intersect the transverse plane of the device at the same angle as that of the flat blades 30 with respect to the axis y-y in Fig. 2.

It is preferable for the most efficient functioning of my device that it be composed of metal having excellent properties of thermal conductivity and that portions thereof be placed in direct thermal contact with a heated portion of the engine so as to take advantage of the heatconducting properties, for better vaporization of the fuel.

My fuel mixing device is adaptable for mounting in most types of internal combustion engines where the fuel is supplied thereto by a carburetor or the like. Preferably it is mounted directly in a fuel intake port of the engine block with portions thereof clamped firmly against adjacent portions of the block in order to be heated thereby. In an automobile engine, for example, the mixture of gasoline and air proceeds from the carburetor through the fuel inlet conduit it toward the engine. At the joint between the end of the conduit Ill and the block l, my improved fuel economizer is most conveniently mounted in a port serving usually a pair of oylinders. The fuel mixture, as it enters my mixing device, may consist of air, gasoline Vapor and droplets of raw liquid fuel. This mixture is moving at high velocity and as it passes through the arcuate blades 30, there is imparted to the stream a smooth whirling motion in a counterclockwise direction as viewed in Fig. 4, substantially without the production of internal turbulence in the stream. The stream next encounters the gently converging twisted blades 26 which serve to impart a whirl thereto in the opposite direction, again without the substantial production of any internal turbulence which would interfere with the smooth flow of the stream. The impartation of whirling motion successively first in one direction and then in the other, but without interna turbulence, promotes the better homogenization of the fuel and air mixture. Furthermore, since both sets of blades are heated substantially to the temperature of the engine block by reason of the thermal conductive characteristics and the proper mounting thereof, the liquid droplets of fuel tend to Vaporize completely before entering the combustion chamber of the engine.

I counteract the normal tendency of the rotary motion to centrifuge liquid particles to the outside Wall by the creation of a Venturi effect at the center of my device. This Venturi action tends to accelerate in a forward direction the central portion of the fuel laden stream passing between the tips of the blades of both sets. This acceleration of a portion of the stream tends to draw back into the stream liquid particles and droplets which may have been thrown toward the outer wall by centrifugal action. The venturi, with respect to the blades 39, is caused by the gentle inward and forward sloping of the recurving inner portions of these blades toward the central axis and in the direction of fiow. A similar Venturi action arises because of the convergence at a small angle of the blades 28 toward the centra1 axis, again leaving a narrowed generally circular opening between the blade tips.

By way of example only, the following are given as typical dimensions of my novel mixing device in one specific embodiment thereof. In general I have found that good results may be achieved according to the invention employing blades 26 having a Width equal to sa of the circumference of the opening in the conduit ID. The other blades will have a corresponding width of approximately Tl of such circumference. The length of the blades 26 should be of the order of 1% times the diameter of the conduit. The length of the blades 38 should be determined in accordance with the following formula: The diameter of the semicircle defined by each such blade should equal approximately of the internal radius of the conduit lt. For best results I have found that the blade tips of both series should define circles whose centers correspond to the longitudinal axis of the device and whose radii are generally Within the limits of lA; to g of the diameter e-z of the conduit. Naturally, the combined width of two blanks, Where two are employed, should approximate the internal circumference of the conduit so that the assembled device will fit snugly therewithin. The distance in a longitudinal direction between the bases of the blades 30 and the bases of the blades 26 is not critical. This distance may conveniently be 1/2 inch for conduits having a diameter a-z of 1%; inches. It will be understood, however, that the foregoing dimensions are given by way of example and not by Way of limitation since I have found that they may vary considerably nevertheless yielding good results in accordance with the invention.

While I prefer to mount my improved fuel mixing device directly in the intake port of the engine block so as to secure maximum benefits therefrom, it is nevertheless possible to mount the same in the outlet of the carburetor or at some intermediate point in the fuel conduit between the carburetor and the engine. I believe, however, that mounting in such other locations yields an inferior performance, first because the blades Will not be heated so efiectively as by direct thermal contact with the engine block, and secondly, that the improved homogenization of the mixture may tend to be lost by passage around sharp corners, etc., on its Way to the firing chamber.

Furthermore, I prefer to form my mixing device in each case from a pair of similar blanks. My reasons for doing so are primarily ease and convenience and economy of manufacture, as well as the adaptability of such a two-part device for installation in fuel conduits which vary somewhat in internal diameter. Nevertheless, it is evident that the device according to the invention may be formed from a single blank or from more than two of such blanks.

The rectangular shape of the blades furnishes a maximum of effective surface while their spacing and twist offer a minimum possible obstacle to fuel now. The special angling, twist and curvature are such as to impart the desired whirling motion while avoiding substantially any production of internal turbulence. I have found, for example, that the more favorable ratio of fuel and oxygen resulting from the use of my device in some types of gasoline engines brings about a fuel saving of from 20-30% and this is a matter of considerable significance where fuel shortages and high prices may become an important factor. The avoidance of loss of volumetric efficiency I believe to be an important factor in producing the saving of fuel. Due to the resultant more perfect combustion there is likewise a reduction in wear on the engine parts and in preignition and detonation by elimination of excessive accumulations of unburned carbon.

The construction of my novel mixing device is such that it is readily adapted without alteration for installation within limits in fuel conduits of a variety of sizes without the need for any auxiliary fittings. Thus, it is adapted for sale to the individual automobile owner who may install the same in his own car without need for expert assistance. Great economies of manufacture are attendant upon the production of the device in the form of pairs of identical blanks which may be bent manually to the proper curvature and tted to a particular fuel pipe. In this respect the invention has a marked advantage over prior art structures in which a single performed unit must be machined to exact size for each installation. Long life is assured by the complete absence of moving parts.

While I have herein disclosed and described a preferred embodiment of the invention, it will be understood that the same is capable of various modifications and changes within the spirit and scope of the appended claims.

I claim:

i. A fuel mixing device for internal combustion engines adapted to be installed in a fuel conduit between the carburetor and an intake port of the engine block thereof, said device comprising a substantially cylindrical hollow body of external diameter corresponding to the internal diameter of said conduit, said body having extending from one end thereof a series of blades each of which is uniformly curved toward the longitudinal axis of said body to substantially semicircular form with interrnediate portions thereof recurving longitudinally outwardly along said axis, the planes of said semicircles intersecting each other substantially at a common point on said longitudinal axis and intersecting the transverse plane of said body at an oblique angle, said blades being closely spaced from each other and overlapping in part substantially throughout their lengths, the tips of said blades being spaced from said axis and lying in a common transverse plane located inwardly of the recurving portions of said blades, and said body having extending from its opposite end a second series of blades, the blades of said second series being elongated and substantially rectangular and defiected inwardly so as to converge at a slight angle uniformly and generally conically upon and with their tips spaced from said longitudinal axis, all of the blades of said second series being uniformly twisted from one end to the other in the same direction to a total twist of approximately 'J to whirl the fuel stream in a direction opposite from the direction of whirl imparted by the blades of said first-named series, said body further having portions arranged to engage and be held by adjacent portions of said conduit for mounting said device in place therein.

2. A fuel mixing device for internal combustion engines adapted to be installed in a fuel conduit between the carburetor and an intake port of the engine block thereof, said device comprising a substantially cyiindrical hollow body composed of sheet metal of external diameter corresponding to the internal diameter of said conduit, said body having struck from one end thereof a series of blades each of which is uniformly curved toward the longitudinal axis of said body to substantially semicircular form with intermediate portions thereof recurving longitudinally outwardly along said axis, the planes of said semicircles intersecting each other substantially at a common point on said longitudinal axis and intersecting the transverse plane of said body at an oblique angle, said blades being closely spaced from each other and overlapping in part substantially throughout their lengths, the tips of said blades being space-:l from said axis and lying in a common transverse plane located inwardly of the recurving portions of said blades, and said body having struck from its opposite end a second series of blades, the blades of said second series being elongated and substantially rectangular and deflected inwardly so as to converge at a slight angle uniformly and generally conically upon and with their tips spaced from said longitudinal axis, all of the blades of said second series being uniformly twisted from one end to the other in the same direction to a total twist of approximately 90 to Whirl the fuel stream in a direction opposite from the direction of whirl imparted by the blades of said first-named series, said body further having ears turned radially outwardly therefrom arranged to engage and be held by adjacent portions of said conduit for mounting said device in place therein.

3. A fuel mixing device for internal combustion engines adapted to be installed in a fuel conduit between the carburetor and an intake port of the engine block thereof, device comprising a substantially cylindrical hollow body consisting of a plurality of interlocked sheet etal members, said body having an external diameter corresponding to the internal diameter of said conduit, said members having struck from one end thereof a series of blades each of which is uniforrnly curved toward the longitudinal axis of said body to substantially semicircular form with intermediate portions thereof recurving longitudinally outwardly along said axis, the planes of said semicircies intersecting each other substantially at a common point on said longitudinal axis and intersecting the transverse plane of said body at an oblique angle, said blades being closely spaced from each other and overlapping in part substantially throughout their lengths, the tips of said blades being spaced from said axis and lying in a common transverse plane located inwardly of the recurving portions of said blades, and said members having struck from the opposite end thereof a second series of blades, the blades of said second series being elongated and substantially rectangular and deflected inwardly so as to converge at a slight angle uniformly and generally conically upon and with their tips spaced from said longitudinal axis, all of the blades of said second series being uniformly twisted from one end to the other to a total twist of approximately 90 in the same direction to whirl the fuel stream in a direction opposite from the direction of whirl imparted by the blades of said first-named series, said members further having ears turned radially outwardly therefrom arranged to engage and be held by adjacent portions of said conduit for mounting said device in place therein.

4. A fuel mixing device for internal combustion engines adapted to be installed substantially in the joint between a fuel conduit and an intake port of the engine block thereof, said device comprising a substantially cylindrical hollow body composed of a plurality of inter-locked highly heat conductive sheet metal members, said body having an external diameter corresponding to the internal diameter of said conduit, said members having struck from one end thereof a series of blades each of which is uniformly curved toward the longitudinal axis of said body to substantially semicircular form with intermediate portions thereof recurving longitudinally outwardly along said axis, the planes of said semicircles intersecting each other substantially at a common point on said longitudinal axis and intersecting the transverse plane of said body at an oblique angle, said blades being closely spaced from each other and overlapping in part substantially throughout their lengths, the tip-s of said blades being spaced from said axis and lying in a common transverse plane located inwardly of the recurving portions of said blades, and said members having struck from the opposite end thereof a second series of blades, the blades of said second series being elongated and substantially rectangular and deflected inwardly so as to converge at a slight angle uniformly and generally conically upon and with their tips spaced from said longitudinal axis, all of the blades of said second series being uniformly twisted from one end to the other to a total twist of approximately 90 to whirl the fuel stream in a direction opposite from the direction of whirl imparted by the blades of said first-named series, said members further having portions arranged to engage and be held in thermal contact with said engine block.

5. A fuel mixing device for internal combustion engines adapted to be installed in a fuel conduit between the carburetor and an intake port of the engine block thereof, said device comprising a substantially cylindrical hollow body composed of a pair of abutting highly heat conductive sheet metal members, said body having an external diameter corresponding to the internal diameter of said conduit, said members having struck from opposite sides thereof coacting slots and fingers interlocked with each other to hold said members together, said members likewise having struck fromone end thereof a series of blades each of which is uniformly curved toward the longitudinal axis of said body to substantially semicircular form with intermediate portions thereof recurving outwardly along said axis, the planes of said semi-circles intersecting each other substantially at a common point on said longitudinal axis and intersecting the transverse plane of said body at an oblique angle, said blades being closely spaced from each other and overlapping in part substantially throughout their lengths, the tips of said blades being spaced from said axis and lying in a common transverse plane located inwardly of the recurving portions of said blades, and said members having struck from the opposite end thereof a second series of blades, the blades of said second series being elongated and substantially rectangular and deflected inwardly so as to converge at a slight angle uniformly and generally conically upon and with their tips spaced from said longitudinal axis, all of the blades of said second series being uniformly twisted from one end to the other to a total twist of approximately in the same direction to whirl the fuel stream in a direction opposite from the direction of whirl imparted by the blades of said first-named series, said member further having mounting projections arranged to engage and be held by adjacent portions of said conduit for mounting said device in place therein.

6. A device as defined in claim 5 in which said oblique angle of the planes of said semicircles is within the limits of from about 30 to 40 from the transverse plane of said body.

'7. A device as defined in claim 5 which is adapted to be mounted at an intake port of said engine block and having at least one portion clamped in good thermal contact with the metal of said block.

8. A device as defined in claim 5 in which the diameter of said semicircles is of the order of 'VS of the radius of said conduit and the length of the blades of said second series approximates three times such radius.

9. A device as defined in claim 8 in which the distance from said longitudinal axis to the tips of the blades of both series is approximately fg to 1/8 the diameter of said conduit.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,298,315 Evans Mar. 25, 1919 FOREIGN PATENTS Number Country Date 177,492 Great Britain Feb. 13, 1922 820,820 Germany Nov. 12, 1951 

5. A FUEL MIXING DEVICE FOR INTERNAL COMBUSTION ENGINES ADAPTED TO BE INSTALLED IN A FUEL CONDUIT BETWEEN THE CARBURETOR AND AN INTAKE PORT OF THE ENGINE BLOCK THEREOF, SAID DEVICE COMPRISING A SUBSTANTIALLY CYLINDRICAL HOLLOW BODY COMPOSED OF A PAIR OF ABUTTING HIGHLY HEAT CONDUCTIVE SHEET METAL MEMBERS, SAID BODY HAVING AN EXTERNAL DIAMETER CORRESPONDING TO THE INTERNAL DIAMETER OF SAID CONDUIT, SAID MEMBERS HAVING STRUCK FROM OPPOSITE SIDES THEREOF COACTING SLOTS AND FINGERS INTERLOCKED WITH EACH OTHER TO HOLD SAID MEMBERS TOGETHER, SAID MEMBERS LIKEWISE HAVING STRUCK FROM ONE END THEREOF A SERIES OF BLADES EACH OF WHICH IS UNIFORMLY CURVED TOWARD THE LONGITUDINAL AXIS OF SAID BODY TO SUBSTANTIALLY SEMICIRCULAR FORM WITH INTERMIDIATE PORTIONS THEREOF RECURVING OUTWARDLY ALONG SAID AXIS, THE PLANES OF SAID SEMI-CIRCLES INTERSECTING EACH OTHER SUBSTANTIALLY AT A COMMON POINT ON SAID LONGITUDINAL AXIS AND INTERSECTING THE TRANSVERSE PLANE OF SAID BODY AT AN OBLIQUE ANGLE, SAID BLADES BEING CLOSELY SPACED FROM EACH OTHER AND OVERLAPPING IN PART SUBSTANTIALLY THROUGHOUT THEIR LENGTHS, THE TIPS OF SAID BLADES BEING SPACED FROM SAID AXIS AND LYING IN A COMMON TRANSVERSE PLANE LOCATEAD INWARDLY OF THE RECURVING PORTIONS OF SAID BLADES, AND SAID MEMBERS HAVING STRUCK FROM THE OPPOSITE END THEREOF A SECOND SERIES OF BLADES, THE BLADES OF SAID SECOND SERIES BEING ELONGATED AND SUBSTANTIALLY RECTANGULAR AND DEFLECTED INWARDLY SO AT TO CONVERGE AT A SLIGHT ANGLE UNIFORMLY AND GENERALLY CONICALLY UPON AND WITH THEIR TIPS SPACED FROM SAID LONGITUDINAL AXIS, ALL OF THE BLADES OF SAID SECOND SERIES BEING UNIFORMLY TWISTED FROM ONE END TO THE OTHER TO A TOTAL TWIST OF APPROXIMATELY 90* IN THE SAME DIRECTION TO WHIRL THE FUEL STREAM IN A DIRECTION OPPOSITE FROM THE DIRECTION OF WHIRL IMPARTED BY THE BLADES OF SAID FIRST-NAMED SERIES, SAID MEMBER FURTHER HAVING MOUNTING PROJECTIONS ARRANGED TO ENGAGE AND BE HELD BY ADJACENT PORTIONS OF SAID CONDUIT FOR MOUNTING SAID DEVICE IN PLACE THEREIN. 